Limbal Stem Cell Deficiency (LSCD) is characterized by ocular pain, poor re-epithelialization, corneal ulceration, conjunctival cell ingrowth and loss f visual acuity. LSCD may be secondary to myriad conditions such as Steven Johnson's Syndrome, ocular cicatricial pemphigoid, chronic inflammation and chemical injury. Transplantation of corneal epithelial stem cells to stem cell deficient corneas has the potential t restore sight to blind eyes. Improving the rehabilitation of patients with stem cell deficiency wil require the ability to better harness and induce the regenerative capacity of adult corneal epithelial stem cells. The proposed research will capitalize upon the slow cycling phenotype of stem cells to aid in identifying, purifying and expanding corneal stem epithelial cell populations using a murine transgenic pulse-chase system. Aim 1 will characterize the gene expression profile of slow cycling cells in the murine cornea. The system will be optimized in subaim 1.1 and isolated slow cycling cells will undergo gene expression analysis in subaim 1.2. Aim 2 will use in vitro and in vivo models to evaluate the regenerative potential of slow cycling corneal epithelial cells. Finally, Aim 3 will identify slow cycling cell related genes that are critical fo corneal epithelium regeneration.